Re: [quicwg/base-drafts] Flow Control Tuning (#3216)

Martin Thomson <> Thu, 28 November 2019 02:45 UTC

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Date: Wed, 27 Nov 2019 18:45:55 -0800
From: Martin Thomson <>
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Subject: Re: [quicwg/base-drafts] Flow Control Tuning (#3216)
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After briefly discussing this with Gorry, I think that we concluded that advice about the frequency of flow control updates would help.

Where flow control limits broadly correspond to the congestion window size, those updates would need to be sent about as often as acknowledgments in order to ensure that flow control didn't stall unnecessarily.  That would be the upper limit; larger flow control limits need proportionally fewer updates.  If flow control limits are very large, updates could be far less frequent.

I don't think that we have an algorithm here, but it seems like this advice would go a long way to avoiding the worst problems.

There's a question then about where this advice goes.  I am inclined to keep this in the transport doc as long as our response only extends to advice in the abstract.

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